Various devices provided with a luminescent panel configured to emit image light have been developed. Luminance of emission elements provided in the luminescent panel decreases with time under a temperature rise of the luminescent panel. The decrease in the luminance of the emission elements is noticeable at the beginning of usage of the luminescent panel. It is known that an aging process for aging emission elements in advance prevents the decrease in the luminance of the emission elements.
Light emission over the entire surface of a luminescent panel is performed at once during the aging process. However, a temperature variation in the plane of the luminescent panel is caused by the aging process with the light emission over the entire surface at once. Emission elements are likely to be susceptible to heat. The temperature variation may cause a life variation among the emission elements. Consequently, a luminance variation may appear on the luminescent panel. An aging process without processing the entire surface at once is proposed (c.f. Patent Documents 1 to 3).
The aforementioned aging process does not sufficiently suppress a temperature variation on a luminescent panel. A luminance variation is likely to happen to a resultant luminescent panel, which may not display images with uniform quality for a long period of time. In short, the luminescent panel has low reliability.
Patent Document 1: JP 2009-187860 A
Patent Document 2: JP S62-143395 A
Patent Document 3: JP S60-244992 A